ArmyGen. Martin E. Dempsey, the newly minted chairman of the Joint Chiefs of Staff, began his tenure this week by setting a tone of defiance and strength.

According to military officials, Gen. Dempsey recently impressed fellow chiefs during a meeting in the secure Pentagon conference room known as the tank.

Toward the end of a vigorous discussion on a sensitive military topic, Gen. Dempsey responded, “We’re not going to do it,” according to one official close to the chiefs.

The chairman, who replaced Navy Adm. Mike Mullen last week, made it clear that military leaders would not be unduly pressured.

No details on the topic or who was pressuring the chiefs could be learned.

Gen. Dempsey stated on his Twitter feed Tuesday: “I met with my team and was able to share some thoughts with them. I trust them to do what’s right and be [the Joint Staff] our nation needs.”

The four-star general held an off-the-record meeting with reporters on Monday in his new office, which is adorned with a large oil painting of Army Gen. George C. Marshall, the historic former Army chief of staff, secretary of state and secretary of defense.

For his desk, Gen. Dempsey brought in a desk used by Army Gen. Douglas MacArthur in the Philippines during World War II.

In an Oct. 1 letter to all U.S. troops, Gen. Dempsey said the U.S. military is “admired by our allies and partners, and we are dreaded by our enemies.”

The chairman’s letter outlined his key priorities as, first, to “achieve our national objectives” — not win — in current conflicts and, second, to “develop Joint Force 2020” as a way to “look beyond current requirements.”

Future modernized military forces must “provide the greatest possible number of options for our nation’s leaders and to ensure our nation remains immune from coercion,” he said.

ANTI-TERROR TRAINERS BLOCKED

The CIA and Department of Homeland Security abruptly canceled a conference in August on homegrown U.S. radical extremism in what officials close to the issue say was an effort to block two conservative anti-terrorism experts from presenting their views.

The conference was slated for Aug. 10 through 12 at agency headquarters in McLean and was to have been hosted by the CIA Threat Management Unit. It was organized by the intelligence subcommittee of the Metropolitan Washington Council of Governments.

“The conference topic is a critical one for domestic law enforcement, and the sponsors — in partnership with the Department of Homeland Security — have decided to delay the conference so it can include insights from among other sources, the new National Strategy for Counterterrorism in an updated agenda,” wrote CIA police officer Lt. Joshua Fielder in an email announcing the postponement in early August.

According to people close to the conference, the event was ordered “postponed” after Muslim advocacy groups contacted the Department of Homeland Security and the White House about the scheduled speakers, who included Stephen Caughlin and Steve Emerson, both specialists on the Islamist terror threat.

Mr. Caughlin, a former Pentagon Joint Staff analyst, is one of the most knowledgeable counterterrorism experts specializing in the relationship between Islamic law and terrorism.

Mr. Emerson, head of the Investigative Project on Terrorism, is a leading expert on Islamic violent extremism, financing and operations.

The Department of Homeland Security did not return a call seeking comment.

CIA spokeswoman Marie Harf said she did not know if Mr. Caughlin or Mr. Emerson will be speakers when the conference is rescheduled at some future date.

“The goal is clear and important — to ensure that conference participants receive material that is as current and comprehensive as possible to support the essential mission of safeguarding Americans here at home,” she said in a statement nearly identical to language used in Lt. Fielder’s email.

One intelligence official said the conference was stopped after the White House learned that Mr. Caughlin and Mr. Emerson were speaking.

This official said that to prevent the two experts from taking part in future conferences, the administration is drafting new guidelines designed to prohibit all U.S. government personnel from teaching classes on Islamic history or doctrine.

The new rules also will seek to prohibit the use of federal funds to pay contractors for such training.

Another official familiar with the conference denied that the postponement was abrupt or in reaction to specific speakers.

“The goal — an entirely appropriate one — is to ensure that an important issue is addressed in the most informative and accurate way possible,” this official said.

“This is a big deal,” former FBI counterintelligence agent David Major said of the postponement.

If new guidelines are used to block experts like Mr. Caughlin and Mr. Emerson, “we will be in ‘1984’ with ‘Newspeak’ on our society in total violation of the First Amendment,” Mr. Major said, referring to George Orwell’s classic novel, in which simplified language is used as a tool to support totalitarian rule.

Matthew Chandler, a DHS spokesman, said the conference will be rescheduled.

“The conference topic is a critical one for domestic law enforcement, and the sponsors decided to delay the conference so it can include insights from, among other sources, the new national strategy for countering violent extremism,” Mr. Chandler told Inside the Ring.

Mr. Chandler said the department along with the National Counterterrorism Center, Justice Department and FBI are developing training programs “focused primarily on better preparing front line law enforcement personnel to identify those behaviors and indicators associated with terrorism-related criminal activity.”

“Equally important is ensuring that the input state and local law enforcement is received so that conference participants receive material that is as current and comprehensive as possible to support the essential mission of safeguarding Americans here at home,” he said.

POLICY BOARD SHIFT

Defense Secretary Leon E. Panetta this week moved to replace key members of the Defense Policy Board, the advisory group of former officials that serves as a brain trust.

“He made it more ‘Democratic,’” one board member quipped about the changes.

Liberals added to the board include former Clinton administration Secretary of State Madeleine K. Albright, former Deputy Attorney General Jamie Gorelick, retired Marine Corps Gen. James Cartwright and Jane Harman, a former Democratic congresswoman from California. Also added: former Chief of Naval Operations Adm. Gary Roughead.

Most notable among the new members is Ms. Gorelick, who was notorious for erecting the so-called bureaucratic “wall” blocking law enforcement and intelligence agencies from cooperating closely before the Sept. 11 terror attacks. The 9/11 Commission blamed the wall as a contributing factor to the failure to stop the Sept. 11 terrorist attacks.

Conservatives no longer on the board include Andrew Krepinevich of the Center for Strategic and Budgetary Assessments, Reagan-era Undersecretary of Defense for Policy Fred Ikle, and retired Marine Corps Gen. Peter Pace, a former chairman of the Joint Chiefs of Staff.

20-YEAR WAR

While the Army and Marine Corps went through big changes to adjust to the war on terror, the Air Force has been steady-as-she-goes.

“When you get into attacking a regime, like we did in Afghanistan and later in Iraq, some principles remain constant,” retired Air Force Gen. T. Michael Moseley told reporter Rowan Scarborough.

“Air power is key, if not decisive, in toppling regimes,” he said. “Some things never change. Post 9/11 has reinforced that in spades.”

Gen. Moseley should know. He’s been a fighter pilot. He commanded the 2003 air war that toppled Saddam Hussein, then ascended to Air Force chief of staff.

He said that once the first fighter wing deployed to Saudi Arabia in 1990 to keep Saddam’s troops from invading from Kuwait, the Air Force began a long war that included bombing Baghdad, enforcing no-go zones in Iraq, bombing Afghanistan and then striking Baghdad again.

It has validated the push for precision munitions, a tanker fleet that keeps jet fighters in the air and unmanned systems that can hunt and strike terrorists.

“When you’ve been doing this for 21 straight years, certain other things become very very clear,” he said, mentioning the ability to deploy quickly and maintaining aircraft far from home.

Being able to hit one building in a congested urban environment or one vehicle on a busy highway is the result of evolving tactics and technology dating back to Vietnam.

“The fundamentals of air power, and the principles of air power and the benefits of air power are constant when you look at combat and you look at extended operations and joint operations,” he said.